Why is sex so great with a narcissist?

My guess is that your experience is an anomaly. I’m sure plenty of narcissists aren’t that great and are even downright awful. But confirmation bias from highly effective narcissists might be skewing your outlook on this.

I’m pretty sure narcissists do a lot of leg work investigating the kind of person who would appreciate their “show.” Maybe they choose those who haven’t had a lot of previous experience and have nothing else to compare “the show” to. Maybe they’ve narrowed down their targets to those who would most likely appreciate “the show” they’re offering. Once they know that you genuinely like “the show” they’re offering, they’re probably going to keep giving you that performance based on your honest reactions (i.e., real, powerful orgasms and climaxes and emotional connections you don’t bother to hide or suppress). They’re most likely not doing this because you like it but instead because you’re confirming their belief that they are amazing lovers. In other words, their egos feed off the intersection of your honest reactions and their need to be considered amazing.  They want to use your sexual satisfaction to control you. They don’t want to give you sexual satisfaction.

But just try to change things up in the sack in a way they’re not 100% in control of. When the relationship evolves (unilaterally from your end), watch all that amazing sex fly out the window when they’re being asked to take your desires into account for real. You want emotional vulnerability and disclosure while you’re doing it? You’re too demanding. You want to be more dominant when before you were submissive (or vice versa)? There’s something wrong with you. You want to integrate sex toys into your partnered sex life? You’re greedy and selfish and they should be enough without introducing all this other stuff. Anything that takes the focus off them and puts it on you will be considered a betrayal.

My advice? Find someone a little less spectacular than the person that “magically” knew everything you wanted at the beginning and rushed you headlong into a relationship. Find someone you’re attracted to whose history you know, that you can take your time with, and who you can discover things with that aren’t all positive or all negative. Best of luck.